GC-MS based characterization and physicochemical analysis of essential oils obtained from Blumea lacera at different growth stages

In the present investigation essential oil yield, physicochemical properties, and chemical constituents of Blumea lacera by using gas chromatography coupled with mass spectrometry (GC-MS) were studied at three phenological stages viz, vegetative, mature green, and flowering. The mature green stage produced the maximum essential oil yield (0.233%). This stage also yielded optimum results for specific gravity (0.994 g/cm³), refractive index (1.494), optical density (0.694), viscosity (12.350 cP), and ester value (69.570 mg KOH/g), indicating high oil quality. GC-MS analysis revealed 72 chemicals throughout all stages, including caryophyllene, alpha-pinene, camphene, linalool, and gamma-terpinene, as well as (3,5-heptadienal, 2-ethylidene-6-methyl-), which was discovered primarily in the mature green stage (39.32%). These findings show that harvesting at the mature green stage maximizes essential oil yield and bioactive chemical concentration, offering important insights into medicinal and aromatic benefits of Blumea lacera.